The present invention generally relates to elevator car door opening and closing apparatus. More specifically the present invention relates to an elevator car door opening apparatus wherein the active door operating mechanism is carried upon the elevator car and car door and an inexpensive, landing door unlocking and opening mechanism is attached to the landing door. A mechanical elevator car door locking mechanism is included which is inherently disabled when the car is within a reasonable distance of a landing site but which otherwise only permits the doors to be opened by an amount insufficient for passengers, within the car, to exit.
Heretofore complex and expensive landing door opening mechanisms have been attached to the landing door at each individual landing site. An example of such a mechanism may be found in U.S. Pat. No. 5,690,188, for an xe2x80x9cElevator Door Systemxe2x80x9d issued to Takakusaki et al. on Nov. 25, 1997 wherein simple, inexpensive car door opening roller assemblies are placed on the car doors and complex, expensive, vane assemblies are placed on each landing site door. This arrangement can prove very costly in a high rise building having a large number of floors served by multiple elevators since the expensive vane assemblies must be provided on each and every landing site door.
The present invention overcomes the shortcomings of the referenced prior art by placing relatively inexpensive landing door opening roller assemblies on the landing doors and placing a more efficient clutch assembly on the elevator car door that engages the landing door roller assembly when the car doors are opened thereby opening both car and landing doors simultaneously in a more efficient and economical manner. Therefore, the more expensive clutch assembly need only be provided on the elevator car and not on each and every landing site door; a definite economical advantage in high rise buildings having a large number of landing sites served by one or more elevator cars.
The present invention teaches a new and improved clutch assembly, attached to the elevator car door comprising an assembly of mechanical links that form an expanding and collapsing mechanical parallelogram that is linked to the car door opening mechanism. The mechanical parallelogram is configured such that two parallel sides thereof provide a pair of vertically oriented gripping links that move laterally toward or away from each other as the mechanical parallelogram expands or collapses. A cam wheel, operated by the door opening mechanism, expands and/or collapses the mechanical parallelogram.
As the elevator car approaches and stops at a landing site, a pair of rollers attached to the landing door""s locking mechanism enters the slot between the vertically oriented gripping links of the mechanical parallelogram. As the elevator doors begin to open, by action of the car door opening mechanism, the cam wheel is caused to rotate thereby collapsing, or closing, the vertical gripping links upon the landing door rollers coupling the landing door to the elevator car door and unlocking the landing doors. With the landing doors unlocked and coupled to the elevator car doors, the car doors and landing doors are opened simultaneously by the car door opening mechanism.
By reversing the elevator car door opening mechanism, the elevator car doors and the landing doors are simultaneously closed and the gripping links are expanded or opened, by the reverse rotation of the cam wheel, thereby releasing their grip upon the landing door rollers whereby the landing doors are again locked and the elevator car is free to move on to another landing site.
In the event of an emergency such as an unexpected electrical power failure, the door opening system, as taught and disclosed herein, further provides a simple and economical way to prevent the opening of the elevator car doors, by onboard passengers, beyond a predetermined amount if the elevator car is not within reasonable distance of a landing zone.
If the elevator car is not within a reasonable distance of a landing site the landing door locking and unlocking rollers will not be between the vertical gripping links of the mechanical parallelogram. Therefore, if the passengers, in a stalled elevator car, push the car doors open, the gripping links, of the mechanical parallelogram will close or collapse toward each other farther than possible when the landing door locking and unlocking rollers are present. The additional travel of the mechanical parallelogram gripping links may be advantageously used to mechanically activate, by appropriate mechanical linkage, a car door latch mechanism that will limit the amount of car door separation.